Which of the following is a cause of hypovolemic shock?

• A. Traumatic hemorrhage
• B. Pulmonary embolism
• C. Myocardial infarction
• D. Anaphylaxis

Answer: (A)

Hypovolemic shock happens when there isn’t enough circulating blood volume to fill the vascular system, so the heart can’t pump effectively enough to perfuse tissues. In trauma, traumatic hemorrhage directly causes this by rapid blood loss, which lowers venous return (preload), reduces stroke volume, and drops cardiac output. The body tries to compensate with tachycardia and vasoconstriction, but if the bleeding isn’t controlled, perfusion deteriorates quickly.

This is why traumatic hemorrhage is the best answer here. Other conditions cause shock through different mechanisms: a pulmonary embolism obstructs blood flow through the lungs and is an obstructive form of shock, not due to volume loss; a myocardial infarction weakens the heart’s pumping ability (cardiogenic shock); and anaphylaxis causes distributive shock from widespread vasodilation and capillary leak, leading to relative, not absolute, hypovolemia.